The embattled Fontana, under investigation by the Mounties for federal cheques used to pay for his son's 2005 wedding reception, is chairman of Trinity Global Foundation.

Last week, Canada Revenue Agency announced taxpayers participating in tax credit schemes will see assessments of their claims for tax credits placed on hold. The agency is targeting taxpayers who receive tax receipts for amounts greater than the amount they donate.

CRA records show donations to Trinity stood at $72,000 in 2008, the year Fontana joined it. By 2011, it issued $72 million in receipts for charitable donations.

That same year, Simple Financial Management of London, a neighbour of Trinity Global on York St., advertised on Kijiji that Trinity investors could turn "as little as $500 into $27,000 of tax credits."

Eleven months ago, Trinity Global partnered with Global Learning Gifting Initiative (GLGI) in a plan to distribute computer "courseware" to people needing to upgrade their education and job skills. Recipients of the courseware were to be the underprivileged and First Nations members.

Fontana has declined interviews about the operation of Trinity, referring questions to his son, Ugo Joseph Fontana, who is president of Trinity.

The younger Fontana told QMI Agency that Trinity Global will not renew its one-year agreement with GLGI.

"We believe it's time for Trinity to now focus its efforts on external grants and its many non gift-in-kind programs."

The grants and programs include helping to feed hungry children across Canada, protect children from the sex trade industry and support local food banks, he said.

In court documents, CRA has called the GLGI tax shelter program a "sham" intended primarily to enrich donors, rather than help those in need.

CRA has denied more than $5.5 billion in donation claims and reassessed more than 167,000 taxpayers who participated in tax shelter schemes. A British Columbia woman, for instance, received tax receipts of $56,000 and $53,000 for a donation of $100.

"All gifting tax shelter schemes are audited and the CRA has not found any that comply with Canadian tax laws," the agency said.

Last month, Nova-Scotia-based Glooscap became the fourth former partner of Global Learning to have its charitable status revoked by the federal government. The CRA said Glooscap received nearly $25 million in cash and goods in 2008 and 2009, but only $900,000 was used for its charitable purposes as millions went to its promoters and GLGI.

After stories about the London mayor and his ties to Trinity, founder Vince Ciccone and its activities appeared in the London Free Press in August, Fontana and Trinity served a "notice of intended action" against the newspaper under the Libel and Slander Act.

The CRA noted this is the busy selling season for such tax shelters and warned if taxpayers are offered a tax receipt larger than the amount donated, "it is very likely not a valid donation."